不同呼吸抑制剂对小麦幼苗根系硝酸还原酶活性的影响

Effect of different respiratory inhibitors on the nitrate reductase activity

为了从生理学角度阐明硝酸还原酶活性(NRA)和呼吸作用的关系,在水培条件下,研究了三羧酸循环的抑制剂之一丙二酸(C3H4O4)、呼吸链抑制剂叠氮化钠(NaN3)、呼吸链解偶联剂2,4-二硝基苯酚(DNP)以及质膜H+-ATPase抑制剂钒酸钠(Na3VO4)对小麦幼苗根系硝酸还原酶活性(NRA)的影响。结果表明,当丙二酸浓度由0增加到1.0 mmol/L时,NRA直线下降,而当丙二酸浓度由1.0 mmol/L再增加到5.0 mmol/L时,NRA几乎保持不变;当NaN3浓度由0 mmol/L增加到1.0 mmol/L时,NRA近直线下降,当NaN3浓度由1.0 mmol/L增加至5.0mmol/L时,NRA下降趋势趋于平缓;在试验浓度范围内,呼吸链解偶联剂2,4-二硝基苯酚对NRA几乎无影响;质膜H+-ATPase的专一抑制剂钒酸钠也对NRA有抑制作用,当Na3VO4浓度由0增加到0.5 mmol/L时,NRA呈直线下降,后随Na3VO4浓度的继续升高,NRA总体呈下降趋势,但下降幅度较为平缓。小麦根系NRA活性依赖于根系呼吸作用的顺利进行,同时也对质膜H+-ATPase有依赖作用。

Water culture experiment was carried out with winter wheat cultivar Xiaoyan 6 as an indicating crop to study the influence of TCA inhibitor （C3 H4 O4 ）, respiration inhibitor （NAN3）, respiration solution coupling medicinal preparation （DNP） and membrane H^＋-ATPase inhibitor （Na3VO4） on the nitrate reductase activity （NRA） of wheat seeding root. This paper could provide physiology basis by explaining the relations of NRA and respiration. The results were as follows：as the concentration of C3 H4 O4 ranged from 0 to 1.0 mmol/L,the NRA was decreased rapidly,and as the concentration increased continuously to 5.0 mmol/L,NRA kept at the same level almostly;as the concentration of NaN3 ranged from 0 to 1.0 to 5.0 mmol/L,the changing tendency of NRA also was same as C3H4O4;membrane H^＋-ATPase inhibitor Na3VO4 also inhibited NRA,as the concentration ranging from 0 to 0.5 mmol/L,NRA showed straight line drop,and after that NRA did not change obviously; under the experimental concentration range, respiration solution coupling medicinal preparation DNP was not influenced. The conclusion of this paper was that the NRA of wheat root relied on respiration of the root and membrane H^＋-ATPase.